These Common Words Have Some Very Uncommon Opposites

Fun with opposites

Many word opposites, or antonyms, are familiar, such as good and bad or black and white. Others are easy to spot because they’re formed by adding prefixes before the word, such as anti-, dis-, or non- (e.g., approve/disapprove).

Other word opposites are, well—surprising to learn that they even exist in the first place. We're taking you through nine unlikely words with counterparts.

nocturnal

Do you tend to stay up late at night? If you're active at night (as are many animals), you’re nocturnal.

Nocturnal ultimately comes from Latin nox, meaning “night.” It is a word most people are familiar with, but what's its opposite?

diurnal

The opposite of nocturnal is diurnal, which means "during the day." The term comes from the Latin diurnalis, meaning “daily,” from diēs, meaning and source of "day."

Humans are typically diurnal, but you rarely hear anyone call us that. The adjective is more often used to describe animals that are active during the day and sleep at night, or to describe something that has a daily cycle, such as the tide or flowers that open by day and close by night.

placebo

A placebo is a harmless pill, medicine, or procedure prescribed for the psychological benefit of the patient. Placebo means “I shall please” in Latin.

A placebo is also an inert substance used in controlled trials to test the efficacy of another drug. Most people know the word placebo, but did you know this word's lesser known opposite?

nocebo

The opposite of placebo is the sound-alike word nocebo, coined in 1961 by one Walter Kennedy. It means “I shall harm.”

Ever heard of the placebo effect? It's when a patient has a positive result from a placebo that’s attributed to their belief in that treatment. Well, the nocebo effect has been called placebo’s evil twin, because warnings about possible side effects can result in a patient experiencing negative symptoms just because they heard about them.

déjà vu

Déjà vu is that eerie feeling you get when you think you’ve previously experienced something that you’re actually encountering for the first time.

The French term literally means “already seen.” Its scientific name is promnesia. But, there's something just as spooky as déjà vu ... its opposite!

jamais vu

The opposite of déjà vu can be considered jamais vu, which is when you do not recognize something (e.g., a word, person) that should be familiar. It also comes from French and means “never seen.”

There’s also a French term for the phenomenon commonly called the tip of your tongue. Presque vu, or “almost seen,” means you can’t immediately recall a familiar word, name, or situation, but you eventually conjure up the elusive memory.

Stockholm syndrome

Sometimes, people who are held hostage form emotional and psychological bonds with their captors. Strange, right?

Well, it does happen, thanks to the stress, dependency, and need to cooperate in such situations. The name for this experience is Stockholm syndrome.

It was recorded in 1978, named for a six-day bank siege in Stockholm, Sweden during which a bank employee became romantically attached to a robber who held her hostage. Another famous example of Stockholm syndrome involves the 1974 kidnapping of newspaper heiress Patricia Hearst.

And, believe or not, there is an opposite to this phenomenon, too.

Lima syndrome

Just as surprising as Stockholm syndrome is its opposite: Lima syndrome, which is when kidnappers develop sympathy for their hostages and let them go without using them as bargaining chips.

The term takes its name from the 1996 Japanese embassy hostage crisis in Lima, Peru. Members of a militant movement took several hundreds hostage at a party held at the residence of Japan’s ambassador to Peru. They were freed, thankfully, within a few hours.

ambidextrous

Roughly 90 percent of humans are righties (right-handed), so that leaves 10 percent as lefties (left-handed).

Only an estimated 1 percent of people are truly (not as the resulting of training, as in baseball) ambidextrous, or "able to use our right and left hands equally well." The word comes from the Latin roots dexter, which means “right-handed, favorable, skilled” and the prefix ambi-, "both."

But, what if you're all thumbs?

ambilevous

Even rarer than people who are ambidextrous are those who are ambilevous, an obscure word taken as "clumsy in both hands" (though sometimes it's treated as a synonym for ambidextrous, making it quite the dextrous word).

The term also comes from the Latin prefix ambi-, meaning "both," and laevus, meaning "left." (Left-handers always get a bad rap. You know what the word sinister originally means in Latin? "Left.")

anonymous

In the digital age, you may know Anonymous as an international network of activists and hackers who do not disclose their identity. The group took its name from anonymous, which means "not named or identified."

We often see the word anonymous used to describe an individual who prefers to remain unknown, such as an anonymous author or an anonymous donor. What do you call yourself if you want that recognition, though?

onymous

The opposite of anonymous is ... onymous! (The an- in anonymous is a Greek prefix, an- or a-, meaning "without.") For instance, He stopped writing anonymous op-eds when his onymous submission was a hit.

Onymous is an relatively obscure, but useful, back formation of anonymous dating back to the 18th century. A back formation is the process of creating a new word by removing some part of it, such making typewrite from typewriter.

catastrophe

You might exclaim "Oh no!" when there’s a catastrophe, or "a sudden disaster that causes damage and suffering."

People have been experiencing catastrophes for eons, but the term dates back to the late 1500s in English. It comes from the Greek katastrophe, meaning “an overturning or a sudden end," originally said of an unhappy ending in a drama.

Fortunately, not everything is doom and gloom ...

eucatastrophe

The opposite of catastrophe is eucatastrophe. J.R.R. Tolkien, who wrote the epic fantasy series The Lord of the Rings, coined the term by simply adding the Greek prefix eu-, meaning "good or well," to catastrophe.

He wanted a word to describe the sudden turn of events at the end of a story, which ensures the protagonist has a happy ending.

distress

When we aren't feeling the anxiety or pain that stress brings, what are we feeling?

eustress

An opposite of distress is eustress, coined by endocrinologist Hans Selye who, like Tolkien, used the Greek prefix eu-, meaning "good or well."

While most of us don’t use this term in our everyday speech—we’re more likely to say “I’m feeling fulfilled”—eustress is sometimes used in psychology to describe a healthy and stimulating level of stress. Good stress.

optimum

Optimum refers to “the best condition" of something, e.g., the optimum work-life balance. The term comes from the Latin optimus, meaning "best." We're afraid to ask, but here goes: What's the "worst"?

pessimum

The word pessimum means "the worst or least favorable condition." The term comes from the Latin pessimus, meaning "worst." Pessimum is generally used in scientific contexts.